1. Field of the Invention
The present invention relates to a clock spring interconnector which electrically connects a fixed member and a movable member rotated with respect to said fixed member by use of a flexible cable such as a flat cable, and more particularly, to a clock spring interconnector suitable for use with a steering system of a vehicle.
2. Description of the Prior Art
In a clock spring interconnector, one end of a flexible cable such as a flat cable is secured to a fixed member whereas the other end thereof is secured to a movable member so that when the movable member is rotated, the flexible cable is wound or unwound on the movable member side whereby the movable member can be rotated a predetermined amount. Such a clock spring interconnector is incorporated into a steering system of a vehicle and used as an electric connecting mechanism between a rotor side and a stator side of an air bag system, for example. In this case, the fixed member is secured to a steering column, and a steering shaft is inserted into and secured to the movable member. When a steering wheel is rotated clockwise or counterclockwise, the turning force thereof is transmitted to the movable member through the steering shaft. When the clock spring interconnector is incorporated into the steering system as mentioned above, the center of rotation of the movable member on the clock spring interconnector side does not always coincide with the center of rotation of the steering shaft on the steering system side, but rather tends to deviate (providing some eccentricity) due to the working accuracy or error in assembly of steering system parts.
In a conventional cable reel, a gap is provided between the movable member and the fixed member so that the movable member can be moved in a radial direction with respect to the center of the fixed member, and the aforesaid eccentricity is absorbed by play in the gap. However, this poses a problem in that the diametral dimension of the movable member increases and the winding diameter of the flexible cable increases accordingly, thus reducing the limited rotational travel of the movable member. Furthermore, when the steering shaft is rotated, an undesired abutment between the movable member and the fixed member repeatedly occurs due to the aforesaid play, which leads to occurrence of abnormal noise during running of the vehicle.